You will need:
Yeast growth experiment in progress; the bottle on the right has warmer water
Your experiment was testing the effect of water temperature on the growth of yeast. Yeast are egg-shaped microscopic cells of fungi which are dormant whilst kept in dry and cool conditions. However, yeast will rapidly divide once exposed to water and a sugar in ideal temperatures. In the right temperature, yeast cells will change the sugar into glucose by using the water plus as enzyme catalyst (invertase). Once the yeast has converted the sugar to glucose fermentation can then occur to produce carbon dioxide and ethanol as per the equation below;
Glucose ⟶ Ethanol + Carbon dioxide
which can be written as...
In your experiment you were trapping the carbon dioxide released during fermentation process. The more active the yeast, the more carbon dioxide the yeast produced! In your experiment the different water temperatures will have produced different results as some water may been too hot for the yeast to survive where as other bottle may been too cold. By introducing a variable to test in your experiment, you're doing real science! The following list of temperatures is worth keeping in mind when assessing your results:
Yeast is used to make bread rise and to ferment beer. There are many different species of yeast, but the one most commonly used in cooking and baking is called Saccharomyces cerevisiae, which is also known as brewer's yeast.
Yeast we used for our science experiment.
Yeast can break down many types of simple carbohydrates (monosaccharides) however they cannot break down complex carbohydrates such as starch. This means that extra enzymes are needed to break down starch into sugars that the yeast can use, for example during beer production we use enzymes from germinating barley to do this.